The present invention generally relates to ignition of pulsed gas discharge lamps, such as a xenon flash lamp.
Gas discharge lamps contain a rare gas, such as xenon or krypton, in a transparent bulb. The gas may be at pressures above or below atmospheric pressure. The lamps have a cathode and an anode through which an electrical current is provided to create an electrical arc. In order for the gas to conduct the electrical energy between the electrodes, the gas is ionized to reduce its electrical resistance. Once the gas is ionized, electrical energy conducts through the gas and excites the molecules of the gas. When the molecules return to their unexcited energy state, they release light energy.
Pulsed gas discharge lamps are operated such that a train of light pulses is emitted from the lamp rather than a continuous light emission. In this type of lamp, the electrical current provided across the cathode and anode is released in short bursts, rather than supplied in a continuous manner. This results in a single discharge or “flash” of light.
Typically, in order to ionize the gas, a high voltage pulse is applied to an ignition electrode on the outside of the bulb, such as a wire mesh wrapped around the outside of the bulb. When a voltage is applied to the wire mesh, the gas inside the bulb is ionized, and the gas may then conduct electricity through the main electrodes. This ionization may also be achieved by an injection triggering method, which applies a voltage directly into a lamp through one or more of the lamp electrodes.
UV light emitted by gas discharge lamps may be used for many applications, including UV curing or sanitization, decontamination, and sterilization. For example, a gas discharge lamp may be placed in close proximity to a conveyor, which moves items to be cured past the lamp. As an item to be cured passes the lamp, the lamp is discharged in order to expose the item to UV radiation. High conveyor line speeds are often required in order to achieve high production rates. This in turn requires the pulsed gas discharge lamp to be operated at a high pulse rate.